The invention relates to rail house cars with openings along their sides. The cars include doors for closing the openings by movement of the doors longitudinally along the sides and laterally into and out of the openings. The invention can be used in cars of the type known as all door cars having four or more door openings along each side or in some special high-cube box cars having but two door openings on each side. One function of the invention being to reduce the deleterious effect of vertical vibrations created by relatively insufficient structural support for the roofs of these cars.
There are two basic types of railroad car doors, the sliding type door and the plug type door. The present invention relates to plug type doors wherein bottom and top rotating crank means moveably support and retain the doors on longitudinal tracks below the doors and within longitudinal retainer means above the doors. Auxiliary crank means are also provided at the top door edges for increased safety. Typically, there are operating cranks opposite each other on the top and bottom edges of the door with the top crank being in association with a longitudinal retainer means and the bottom crank being in association with a longitudinal track means. These aligned cranks are tied together for unitary angular operation by means of pipes which may be selectively manually driven by various mechanical means such as levers, rack and pinion combinations, push rods and clevises, etc. In any of the types of plug doors involved, the movement of the cranks creates the lateral movement of the door into and out of the door opening, the door being "plugged" into the opening when it is laterally in the opening and free to move along the track and retainer longitudinally of the car when it is not in the "plugged" condition.
In both the multi-opening cars known as all door cars and in some special single or double opening cars known as high-cube box cars, because of vertical vibrations caused by insufficient roof support, there has been a problem of the rollers which move along and against the inside surface of the longitudinal retainer means at the top of the doors in association with the cranks damaging the inner surfaces upon which the rollers move. The rollers provide the bearing surfaces for movement of the doors along the cars; and when these rollers were fixed in position such as by the doors being plugged in a given opening, the tangential line of contact of the rollers with the inner surfaces of the longitudinal retaining means created wear. After extended use, the rollers end up gouging and frictionally eroding their way along the line of contact through the surface of the retaining means until the retaining means is weakened to a non-functional condition, either by breaking, bending or opening to the point that the rollers may not move along the longitudinal retainer surface in the manner required. The present invention is devised to eliminate or to at least minimize this action of the rollers against the surfaces of the retainer means and the resulting damage to the car created thereby due to the relative motion between the roller and the retainer means surface during movement of the rail house car.
In its simplest form, the invention relates to providing a face to face, surface to surface contact where the crank means ends engage the longitudinal retainer means as opposed to the tangent line to surface contact which has heretofor existed. To make this provision, recesses are provided in the longitudinal retaining means at the areas which most often come in contact with the crank means ends and the crank means ends have been provided with rollers surrounded by flat or slightly tapered faced skid or pad means, generally castings, which broaden the area of contact so that the crank means roller ends do not as easily damage the retainer means from friction during relative motion of the crank means and the longitudinal retaining means during movement of the house car. The means for this solution will be easily discerned from the drawings and brief description of the invention.